1. Field of the Invention
The present invention is generally related to a propeller torque transmitting device and, more particularly, to a group of components that advantageously use axial splines, helical splines, and springs which can be combined into a cartridge, or assembled unit, which is configured to be assembled into a propeller and onto a propeller shaft to facilitate the incorporation of a shock absorbing component within the operating structure of a marine propeller.
2. Description of the Related Art
Those skilled in the art of marine propulsion devices are familiar with many different techniques and apparatus for attaching a marine propeller to a propeller shaft of a marine propulsion device. Many of these attachment schemes incorporate components which are intended to react to relative rotational movement between the propeller and the propeller shaft. The resulting relative rotation between the propeller and its shaft can be absorbed by some of the various attachment devices that are known to those skilled in the art. In addition, when a marine propulsion device is shifted from neutral to a forward gear position, the sudden discrepancy in rotational speed between the propeller shaft and the propeller can cause an effect on the propeller. Various types of known connection devices are intended to absorb or partially absorb this shock.
U.S. Pat. No. 2,751,987, which issued to Kiekhaefer on Jun. 26, 1956, discloses a resilient propeller mounting and slip clutch responsive to propeller thrusts. It relates to propellers for outboard motors and the like and particularly to mounting of the propeller to protect the propeller against damage due to striking submerged objects.
U.S. Pat. No. 4,642,057, which issued to Frazzell et al. on Feb. 10, 1987, discloses a shock absorbing propeller. It includes a sleeve member for mounting on a propeller shaft, a propeller having an inner hub which fits over the sleeve member and a cushion member fitting between the sleeve member and the propeller inner hub. The sleeve member includes radially extending projections registering with channels in the hub to positively drive the propeller, even in the event of failure of the cushion member. The propeller has an outer hub surrounding the inner hub to define an exhaust gas passageway through the propeller.
U.S. Pat. No. 5,244,348, which issued to Karls et al. on Sep. 14, 1993, discloses a propeller drive sleeve. The shock absorbing drive sleeve is provided by a molded plastic member directly mounting the propeller hub to the propeller shaft. The sleeve has a rearward inner diameter portion engaging the propeller shaft in splined relation, and a forward inner diameter portion spaced radially outwardly of and disengaged from the propeller shaft. The drive sleeve has a rearward outer diameter portion, and a forward outer diameter portion engaging the propeller hub.
U.S. Pat. No. 5,322,416, which issued to Karls et al. on Jun. 21, 1994, discloses a torsionally twisting propeller drive sleeve. It is disposed between the propeller shaft and the propeller hub and absorbs shock after the propeller strikes an object by torsionally twisting between a forward end keyed to the propeller hub and a rearward end keyed to the propeller shaft.
U.S. Pat. No. 5,415,575, which issued to Karls on May 16, 1995, discloses a marine drive propeller clutch. It releases a propeller from the driving engagement of a propeller shaft when the propeller hits an object with sufficient force to otherwise cause damage to the marine drive. A clutch with first and second clutch members disengageably drives the propeller with a plurality of clutch teeth on one of the clutch members and a corresponding plurality of clutch sockets on the other.
U.S. Pat. No. 5,484,264, which issued to Karls et al. on Jan. 16, 1996, discloses a torsionally twisting drive sleeve and adapter. The sleeve and adapter are disposed between the propeller shaft and the propeller hub where the drive sleeve absorbs the shock of the propeller striking an object by torsionally twisting a forward end of the drive sleeve which is keyed to the propeller hub and where the adapter is keyed to the propeller shaft and the drive sleeve is keyed to the adapter.
U.S. Pat. No. 5,630,704, which issued to Gilgenbach et al. on May 20, 1997, discloses a propeller drive sleeve with asymmetric shop absorption. The sleeve mounts a marine drive propeller to a propeller shaft and has an asymmetric spring rate such that the sleeve has a higher spring rate and greater torque bearing capability for the forward boat direction and a softer spring rate and greater shock absorption for the reverse boat direction to protect the weaker reverse drive components of the gear train.
U.S. Pat. No. 6,478,543, which issued to Tuchscherer et al. on Nov. 12, 2002, discloses a torque transmitting device for mounting a propeller to a propeller shaft of a marine propulsion system. The device is used in conjunction with a marine propulsion system and provides an adapter that is attached in torque transmitting relation with a propulsor shaft for rotation about a central axis of rotation. The first insert portion is attached in torque transmitting relation with the adapter and a second insert portion is attached in torque transmitting relation with a hub of the propulsor hub which can be a marine propeller or an impeller.
U.S. Pat. No. 6,799,946, which issue to Neisen on Oct. 5, 2004, describes a propeller assembly. It includes an interchangeable drive sleeve, an inner hub, a biasing member forcing the drive sleeve into contact with the inner hub, and a propeller including an outer hub in which the drive sleeve and inner hub are inserted. The drive sleeve can include a plurality of teeth that engage a plurality of teeth on the inner hub.
U.S. Pat. No. 7,086,836, which issued to Sheth et al. on Aug. 8, 2006, discloses a dual rate torque transmitting device for a marine propeller. The mechanism for a marine propulsion system provides a connector mechanism, a first torque transfer mechanism, and a second torque transfer mechanism. A plurality of rods can provide the first torque transfer mechanism and a polymer component is shaped to provide the second torque transfer mechanism.
U.S. patent application Ser. No. 11/488,359 (M10016) which was filed by Behara et al. on Jul. 18, 2006, discloses a damping mechanism for a marine propeller. A transmission for a marine propulsion device is provided with a movable member that responds to relative rotational movement between it and a driving shaft and an axial movement relative to the driving shaft and to a driven component. This axial movement is directed against one of two spring components which resist the axial movement. During the compression of either of the spring components, rotation of the spring component is non-synchronous with the driving component during a brief period of time. Also, the driven component is decoupled at least partially from torque transmitting relation with the driving component during the axial movement of the movable member relative to the driving and driven components.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
It would be significantly beneficial if a torque coupling mechanism could be provided for a marine propeller which is easily assembled, as a module, to both the marine propeller and a propeller shaft while retaining the beneficial function of absorbing shock that can cause relative rotation between the marine propeller and its propeller shaft. It would be particularly beneficial if this type of apparatus could be configured to absorb a greater degree of relative rotation than is possible with currently known devices.